Is it true that girls have more taste buds than boys and, if so, why? (Josh, age 11)

Answer by: Professor Tim Jacob - Cardiff University

Some people are ‘supertasters,’ some are ‘regular tasters’ and others are ‘non-tasters’ based on their ability to taste specific bitter substances (the chemical name of one of them is n-propyl thiouracil or n-PROP for short). Some people do not detect these substances at all, while others find them intensely bitter and offensive. About a quarter of people (25%) are supertasters, half (50%) are regular tasters and a quarter are non-tasters. Women are supertasters or non-tasters more frequently, while men tend to be regular tasters – this applies to children as well. The anatomical data also support the gender difference; women do indeed have more fungiform papillae (the little red dots on the front surface of your tongue) and more taste buds. The ability to taste or not taste these bitter substances appears to be determined by genetics. Apparently, if you have a double copy of the gene that confers sensitivity to bitter taste, then you are a supertaster. If you have one copy, you are a regular taster and if you have none, you are a non-taster. The tongues of supertasters are physically different from non-tasters. Supertasters have more taste buds on their tongue. Consequently, there are more taste buds to send bitter messages to the brain. Our age plays a role in the number of taste buds on our tongue. Children have the most taste buds, which may explain why they are more sensitive and tend to be more fussy about what they eat. There is a decrease in taste sensitivity with ageing in women. Only about 7% of women aged 65 and older were supertasters as compared with the expected 25% in younger women. Supertasters tend to be thin and non-tasters tend to be heavier. Possibly because of the intensity of flavours, supertasters tend to eat less food. Non-tasters, on the other hand, may eat more while searching for a fuller flavour. In evolution, supertasters may have had some advantage since many toxins are bitter in taste. This is particularly important for women since they are responsible for the diet of the baby in the womb and also after birth while the baby is being breast fed. Interestingly, the sensitivity of women to bitterness commonly increases during the first trimester of pregnancy when the foetus is most vulnerable to damage by many toxins. For example, in some women who typically love coffee, a strong aversion to coffee’s bitterness occurs as soon as they become pregnant.